Berlin: Boris Becker was once a wealthy German hero. But the retired German tennis champion has lost much of his fortune, as well as his reputation, to a costly divorce, a messy settlement to a pregnant lover, a string of failed businesses and a battle with tax authorities.

The man with six Grand Slam titles now even faces the spectre of jail, the latest humiliation to hit the fallen idol whose first Wimbledon title in 1985 triggered a German tennis boom and wave of unparalleled national pride.

Munich state prosecutors are investigating Becker, 34, on tax evasion charges. They allege that early in his career he told them his residence was in Monaco, a tax haven, while he was in fact living in Munich.

Prosecutors accuse Becker of withholding taxes from German authorities between 1991 and 1993 worth 10.4 million marks (5.3 million euros). If convicted, he could face up to six years in jail.

“There is sufficient reason to suspect tax offences,” said the head of the Munich public prosecutor’s office Manfred Wick last month. A spokeswoman denied reports that Becker had agreed to a settlement and would pay back taxes to avoid any prosecution.

Becker has declined to comment on the investigation. His communications director Robert Luebenoff did not return calls. “I can’t make any comment on the matter,” he told the Bild this week. Germany’s leading tabloid has closely tracked Becker’s romantic interests and business failings over the last three years.

In Becker’s first interview since splitting up recently with an Iranian-born American girlfriend, who has since become a celebrity in Germany solely because of the 151-day romance, he offered some confusing thoughts about his outlook on life.

The tax dispute is only the latest calamity to hit Becker, who retired from the ATP tour three years ago but has recently returned to the court for exhibition matches, where he showed some flashes of his former prowess but also signs of rust.

Becker will play American John McEnroe in such a match at the US Open on September 7. Tuning up for that, he beat Michael Stich on Sunday in Berlin in a contest where both ageing German players at times seemed to move in slow motion.

“I never would have thought that there was so much interest,” said Becker after beating Stich 7-5, 6-4 before a sell-out crowd of 7,000 and a national television audience.

Becker’s company organised the match and he earned 50,000 euros according to a report in the Sueddeutsche Zeitung. Despite collecting an estimated 150 million euros during his 15-year tennis career, Becker is apparently in need of money.

“I’ve long had the feeling that money was starting to get tight for Becker,” said his former adviser Nickolaus Becker in an interview with the Munich-based Focus magazine. The magazine quoted a former tax adviser as warning him years ago: “You spend 120 per cent of the money you earn.”

Becker recently sold his villa in Munich and moved into a hotel. He has also sold a flat in Monaco.

The cost of living was something Becker never had to worry about during his career, which included three Wimbledon titles, two Australian Open crowns and one US Open victory.

But a series of problems since his tennis days has sullied his reputation and blown holes in his savings.

A failed business, the collapse of his marriage, a messy divorce, a love child conceived in a cupboard at a trendy London restaurant and a fling with a German rap singer have made Becker a regular feature on tabloid front pages and the butt of countless jokes.

“Maybe Becker is always on the newspaper front pages because he’s afraid of being forgotten,” said his former coach Guenter Bosch. “If he keeps going like this he’ll end up like a washed-up pop star. I hope he can get his act together.”

Bosch, who said he was appalled at the prospect that Becker could go to jail, said Becker’s drive and refusal to take advice from anyone made him a great tennis player but a failure off the court.

“He’s a man of many faces,” added Bosch, who said he had not had a long conversation with Becker in years. “What could we talk about' His affairs'....But Boris as a prisoner in jail' That’s impossible. That can’t happen.”

Becker was once a favourite of German advertisers eager to use him to promote their wares. But no longer. “Boris Becker is now practically worthless for advertisers,” Udo Klein-Boelting, executive of the BBDO advertising group, told Focus. “His image has been transformed from that of a winner into a loser.”

In a recent survey for the Frau im Spiegel magazine, more than half the respondents said Becker was no longer a credible role model because of the problems with the tax authorities.

Becker’s life started to unravel in late 1999 when he and his wife Barbara separated.

They had been one of Germany’s most prominent couples, appearing at celebrity parties and on glitzy magazine covers, and had two children. The shock split after a seven-year marriage dominated front pages for months.

Becker revealed he was having an affair with singer Sabrina Setlur, billed Germany’s most erotic woman, at about the same time that his estranged wife was filing for divorce in Florida. Becker agreed to a multi-million-dollar settlement.

It also emerged that Becker had fathered a child in London with a Russian model after a sexual encounter in the laundry cupboard of a Japanese restaurant after his final Wimbledon match, at the time when his wife was pregnant with their second son.

Becker agreed to pay child support, reportedly some $2.8 million, after a paternity test confirmed he was the father. He has been criticised by German tabloids for not visiting the child, a girl who bears a striking resemblance to him.

Becker said his personal life spun into crisis after his father, Karl Heinz, died in 1999. “I was completely overwhelmed,” he said. “I was a mess. I’ve done nothing more than try to regain control of my life.”